1. Field of the Invention
This invention relates to a developer apparatus that is applicable to image-forming equipment such as copiers, facsimile machines, and printers. In particular, it relates to a developer apparatus equipped with a developer that renders electrostatic images formed on an image carrier into visible images, a toner storage unit that contains the toner to be supplied to the developer, and a toner residual amount detection means having a light-emitting unit and a light sensor and that detects the amount of residual toner in the aforementioned toner storage unit.
Among the known toner residual amount detection means that are employed in this type of developer apparatus is one that contains, at a minimum, the end of a light transmission component that follows a light source that comprises a part of said detection means and the end of a light transmission component that follows a light sensor device, such that these ends are provided along the interior wall of the toner storage unit within the toner storage unit in which toner can be contained. (Refer to the OFFICIAL GAZETTE FOR UNEXAMINED JAPANESE PATENT APPLICATIONS H2-17112 (1990).)
If the light transmission component of said detection means, as in the aforementioned constitution, is provided along the interior wall of the toner storage unit, the light path must be bent within the toner storage unit in order to ensure that the light emitted by the light-emitting unit reaches the light sensor. To bend the light path, optical fibers and other expensive materials are used as light transmission components. This increases the manufacturing costs of the toner residual amount detection means, which results in an overall increase in the manufacturing costs for the developer apparatus as a whole.
The present invention has been developed in view of the issues identified above. The purpose of the present invention is to provide a developer apparatus equipped with a toner residual amount detection means that is capable of determining whether toner remains in the developer.
2. Brief Summary of the Invention
To accomplish the above objective, one aspect of the invention is characterized as follows: In the developer apparatus equipped with a developer that renders electrostatic images formed on an image carrier into visible images, a toner storage unit that contains the toner to be supplied to said developer, and a toner residual amount detection means having a light-emitting unit and a light sensor and that detects the amount of residual toner in the aforementioned toner storage unit; a developer apparatus comprising: forming a hollow recess facing the light-emitting unit and a recess facing the light sensor by causing the walls of the aforementioned toner storage unit, located opposite the aforementioned light-emitting unit and the light sensor, to protrude into the inside of the aforementioned toner storage unit; forming transparent units on the opposite walls of said pair of hollow recesses relative to the light received from the light-emitting unit; forming a reflector, on an outer surface of the aforementioned recess opposite the light-emitting unit, that reflects the light from said light-emitting unit to the aforementioned transparent unit on said recess located opposite the light-emitting unit; and forming a reflector, on the aforementioned recess opposite the light sensor, that reflects the light that has passed through the aforementioned transparent unit on the aforementioned recess opposite the light-emitting unit, to the aforementioned light sensor.
According to other aspects of the current invention, the light emitted from the light-emitting unit enters the recess opposite the light-emitting unit. This light is reflected by the reflector located on the recess opposite the light-emitting unit and passes through the transparent unit located on the recess opposite the light-emitting unit. Moreover, the light that has passed through the transparent unit passes through the area in the toner storage unit in which toner can exist. If no toner is present in the toner storage unit, the light passing through this area directly passes through the transparent unit located on the recess opposite the light sensor, and the light is reflected by the reflector located on the recess opposite the light sensor and is detected by the light sensor. On the other hand, if toner still exists in the toner storage unit, and between the transparent units formed on the walls located on the pair of hollow recesses, the light reflected by the reflector on the recess opposite the light sensor passes through the transparent unit on the recess opposite the light-emitting unit. After that, the light is blocked by the toner and is consequently prevented from being sensed by the light sensor. Thus, the light emitted by the light-emitting unit is bent by using a reflector that is provided on the opposite recesses. The light beam is thus made to pass through the area in which toner could exist and is guided to the light sensor. In this manner, whether toner still exists in the toner storage unit is determined on the basis of whether light is sensed by the light sensor.
According to another aspect of the invention, the light beam emitted by the light-emitting unit is directed by the reflectors that are provided on an outer surface of the recess opposite the light-emitting unit and on the recess opposite the light sensor. The light beam is made to pass through the area in which toner could exist, and to reach the aforementioned light sensor. In order to determine whether some toner is remaining in the toner storage unit on the basis of whether the light sensor has sensed the light beam, the wall parts of the toner storage unit that protrude to the light-emitting unit and the light sensor are made to protrude to the interior of the aforementioned toner storage unit, thus forming a hollow recess opposite the light-emitting unit and a hollow recess opposite the light sensor. Therefore, an expensive material, such as an optical fiber, does not need to be used in the part corresponding to the aforementioned pair of recesses. Therefore, the present invention offers the advantage of allowing the production of low-cost equipment.